Systems and methods for managing sharp transitions for powder coating

ABSTRACT

An apparatus includes a component having an edge feature that has a radius of curvature. The apparatus includes an underlayer arranged over the edge feature and configured to increase the radius of curvature of the edge feature. The apparatus includes a powder coating arranged over the component and over the underlayer to form a continuous layer. The underlayer is configured to remain under the powder coating. The underlayer helps the powder coating achieve a more uniform thickness over the edge feature. The apparatus is formed by applying an underlayer to a first region of the component to form an underlaid component. The first region includes the edge feature. A powder coating is applied to the underlaid component. A masking layer may be applied to a region other than the first region, and after powder coating, the masking may be removed to expose a surface of the component.

INTRODUCTION

The present disclosure is directed to preparation for powder coating,and more particularly, to the use of an underlayer to improve powdercoating.

SUMMARY

In some embodiments, the present disclosure is directed to an apparatusthat includes a component, an underlayer, and a powder coating. Thecomponent includes at least one edge feature having a radius ofcurvature. The underlayer is arranged over the at least one edge featureand is configured to increase the radius of curvature of the at leastone edge feature. The powder coating is arranged over the component andover the underlayer to form a continuous layer. The underlayer isconfigured to remain under the powder coating as a permanent,non-serviceable design feature.

In some embodiments, the component includes a cooling assembly formedfrom sheet metal, wherein the at least one edge feature comprises ajoint at an edge of the sheet metal. For example, the component mayinclude a cooling jacket of a battery module having sharp edges.

In some embodiments, the component further comprises a region that isexposed, wherein the region does not coincide with the underlayer. Insome embodiments, the component includes a busbar, and the region isconfigured to be electrically coupled to an electrical circuit. Forexample, if the component is a busbar, in some embodiments, theunderlayer is electrically insulative.

In some embodiments, the component includes one or more recess features,and the underlayer is arranged to cover the one or more recess features.For example, the powder coating need not penetrate into the recesses,but rather may coat the underlayer arranged over the recesses. Forexample, in some embodiments, the component includes a bracketingsupport such as a mounting bracket of a battery module.

In some embodiments, the underlayer includes a tape. For example, insome such embodiments, the tape includes a thermoset tape, a maskingtape, a heat activated tape, any other suitable tape, or any combinationthereof.

In some embodiments, the underlayer comprises a thickness selected toprovide a predetermined spatial dimension of the apparatus.

In some embodiments, the component includes an electrically conductivematerial. For example, the component may be metal.

In some embodiments, the present disclosure is directed to an apparatusthat includes more than one component. In some embodiments, theapparatus includes a first component, an underlayer, a powder coating,and a second component. The first component includes at least one edgefeature having a radius of curvature, and is electrically conductive.The underlayer is arranged over the at least one edge feature and isconfigured to increase the radius of curvature of the at least one edgefeature. The second component is arranged a distance from the firstcomponent is also electrically conductive. The powder coating isarranged over the first component and over the underlayer to form acontinuous layer. The underlayer is configured to remain under thepowder coating provides dielectric protection against shorting betweenthe first component and the second component.

In some embodiments, the present disclosure is directed to a method forcoating a component comprising an edge feature. The method includesapplying an underlayer to a first region of the component to form anunderlaid component, and applying a powder coating to the underlaidcomponent to form a coated component. The first region includes the edgefeature, which has a first radius of curvature. The underlayer forms asecond radius of curvature at the edge feature larger than the firstradius of curvature. The underlayer is configured to remain on thecomponent under the powder coating.

In some embodiments, the underlaid component has an exterior surface,and the method includes preparing the exterior surface for the powdercoating.

In some embodiments, the method includes applying a masking layer to asecond region of the component. The first region and the second regiondo not overlap. In some embodiments, the method includes removing themasking layer after applying the powder coating to expose the secondregion of the component.

In some embodiments, applying the powder coating includes spraying apowder onto the underlaid component, and curing the powder to from thepowder coating.

Curing the powder coating includes increasing a temperature of theunderlaid component to cause the underlayer to adhere more strongly tothe component.

In some embodiments, applying the underlayer includes applying a tape tothe first region. In some such embodiments, the tape includes athermoset tape, a masking tape, a heat activated tape, any othersuitable tape, or any combination thereof.

In some embodiments, the method includes selecting the underlayer basedat least in part on a material of the component. In some embodiments,the method includes selecting the underlayer based at least in part on adesired electrical property of the coated component.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure, in accordance with one or more variousembodiments, is described in detail with reference to the followingfigures. The drawings are provided for purposes of illustration only andmerely depict typical or example embodiments. These drawings areprovided to facilitate an understanding of the concepts disclosed hereinand shall not be considered limiting of the breadth, scope, orapplicability of these concepts.

It should be noted that for clarity and ease of illustration thesedrawings are not necessarily made to scale.

FIG. 1 shows a flowchart of an illustrative process for using anunderlayer to improve powder coating, in accordance with someembodiments of the present disclosure;

FIG. 2 shows a flowchart of an illustrative process for using anunderlayer and mask to improve powder coating, in accordance with someembodiments of the present disclosure;

FIG. 3 shows stages of layering and coating an illustrative coolingassembly, in accordance with some embodiments of the present disclosure;

FIG. 4 shows a perspective view of an illustrative busbar, which hasbeen powder coated, in accordance with some embodiments of the presentdisclosure; and

FIG. 5 shows an illustrative mounting bracket, which has been powdercoated, in accordance with some embodiments of the present disclosure.

DETAILED DESCRIPTION

A battery module may include components having sharp edges ortransitions, for example, along sides and corners. As part of themanufacturing process, a component may be powder coated with anelectrically insulative material. Powder coating typically results in athinner layer of material being deposited along sharp transitions suchas edges and corners. Such relatively thinner layers of material atthese sharp transitions may fail to meet desired electrical insulativerequirements. Further, because of edge effects, sharp transitions aremore susceptible to electrical shorting. Although sharp transitions maybe machined to make them less sharp, this machining can be timeconsuming and costly. Alternatively, additional powder coating materialcould be added to the object, but in some circumstances an overallthicker coating would negatively impact heat transfer properties of thecomponent. After powder coating, application of an insulative material(e.g., Kapton tape or PET tape) to the sharp transitions may helpprovide insulation, but such materials can be costly and can peel awayover time. In locations where the coating is thinner, pinholes, burrspoking through the coating, or other defects form and present potentialfailure locations. For example, aside from electrical isolationconsideration, penetration of water, water and ethylene glycol (WEG)coolant, or volatile organic compounds (VOC) from vented cell contentsthrough the coating may degrade both the part that is supposed to becoated for protection as well as the adhesion between the powder coatingand the part itself. Degradation may include, for example, softeningfrom water absorption, corrosion from exposure to salt and water (in thecase of coating ferrous metals, common in battery packs), oracceleration of propagation of stress cracks at the powder coat—partinterface. Accordingly, it is desirable to achieve proper insulativeproperties at sharp transitions without using excessive powder coatingmaterial or adding expensive insulative material afterwards.

FIG. 1 shows a flowchart of illustrative process 100 for using anunderlayer to improve powder coating, in accordance with someembodiments of the present disclosure. Panel 150 illustrates process 100based on illustrative component 151. In an illustrative example, process100 includes applying a masking tape to any sharp transitions of anobject, powder coating the object, and leaving the masking tape on theobject (e.g., while the object is used as intended).

Step 102 includes receiving a component (e.g., component 151) having atleast one edge feature (e.g., corners of component 151). The componentmay include a cooling component (e.g., a cooling plate or coolingjacket), a busbar (e.g., a terminal busbar of a battery pack), asidewall or mounting bracket of a battery pack, any other suitablecomponent having an edge feature, or any combination thereof. Step 102may include arranging the component (e.g., in a holder, fixture, orstand), selecting the component (e.g., based on part number, serialnumber, or type), preparing the component (e.g., grinding, sanding,etching, cleaning, or applying any other suitable preparation), anyother suitable action, or any combination thereof.

Step 104 includes applying an underlayer to the at least one edgefeature. The underlayer (e.g., shown by layers 152 and 153) may includea tape such as, for example, a masking tape, a thermoset tape (e.g.,having a thermosetting epoxy embedded), a heat-activated tape, any othersuitable tape, or any combination thereof. The underlayer may beelectrically conductive, dielectric, thermally conductive, thermallyinsulative, or any suitable combination thereof. The underlayer may haveany suitable thickness profile.

For example, an underlayer may have a uniform thickness, a varying ortapered thickness, or a combination thereof. In some embodiments, step104 includes selecting the underlayer based on the component received atstep 102.

Step 106 includes applying a powder coat (e.g., shown by coating 154) tothe component and underlayer. Applying the powder coat may includepreparing the exposed surface, spraying a powder on the component andunderlayer, and curing the powder to form an overlayer. Preparing theexposed surface may include blasting with air to remove particles,blasting with particles to abrade the exposed surface, washing or othercleaning, plasma treating, performing any other suitable action toprepare for spraying, or any combination thereof.

In an illustrative example, process 100 provides an improved powdercoating process for coating sharp transitions, resulting in a moreconsistent coating thickness and improved electrical insulativeproperties. Process 100 includes using a masking tape in anunconventional manner. For example, a masking tape is typically used toprevent a powder coating from being applied to a portion of the object.For example, if an object comprises a window portion, masking tape couldbe used to protect that region during powder coating. The power coatingwill flow over the masking tape during electrospray of the powder andgelling, and is then removed from the window portion (e.g., the tape ispeeled off the object after the coating has hardened via a curingprocess). The present disclosure makes use of a masking tape in adifferent manner, to enable the object to receive a more consistentpowder coating layer in the desired area where the masking tape isapplied (e.g., over the sharp transition such as an edge feature). Inconventional uses, the tape is necessarily removed to expose the objectsurface, which is free from a powder coated layer, and the tape wouldhinder any further processing of the surface if left in place.

As illustrated, component 151 includes a rectangular shape having 4sharp corners. Tape is applied to form layers 152 and 153 (e.g.,underlayers), by wrapping the tape around the edges and extending ashort distance along the top and bottom surfaces. Component 151 is thenpowder coated to form coating 154. Layers 152 and 153 smooth out thesharp corners of component 151, which enables coating 154 to maintain asufficient thickness around the edges, which provides several benefits.For example, coating 154 allows component 151 to exhibit sufficientelectrical insulative properties at the sharp transitions. Further, bypowder coating over the entirety of layers 152 and 153 and the boundarywhere layers 152 and 153 end (e.g., and the exposed surface of component151 begins), layers 152 and 153 are encapsulated under the powdercoating, which prevents layers 152 and 153 from peeling away laterduring use of component 151 as coated. Further, the use of an underlayer(e.g., layers 152 and 153) may reduce manufacturing cost by eliminatingthe use of more expensive insulators applied over coating 154, such asKapton or PET tape. For example, because layers 152 and 153 allow bettercoating at the corners, any tape applied over coating 154 does not needto be electrically insulative to mitigate thinner coating regions (e.g.,as would be required if layers 152 and 153 were not present).

Features of a component may have a corresponding radius of curvature.For example, edges of component 151 may include a relatively smallradius of curvature, and thus may be susceptible to a thinned powdercoating at those edges. In general, sharper features will exhibit alesser radius of curvature (e.g., an extremely sharp corner has a radiusof curvature approaching zero), and smoother features will exhibit agreater radius of curvature (e.g., a substantially flat surface has aradius of curvature approaching infinity). A radius of curvature, asused herein, may refer to a local radius of curvature, a range of radiiof curvature, an effective radius of curvature, an average radius ofcurvature, any other suitable metric corresponding to sharpness, or anycombination thereof.

In an illustrative example, in some embodiments, a tape used to formlayers 152 and 153 may have relatively weak adhesion to metals (e.g.,such as painter's tape) so that it can be peeled off the part afterpowder coating. In some embodiments, layers 152 and 153 are formed usingtapes that exhibit good adhesion to metals for permanent bonding. Insome embodiments, applying coating 154 includes baking at an elevatedtemperature, which may melt the tape at least partially. In somecircumstances, melting makes it adhere more strongly to the surface ofcomponent 151, thus making peeling off of layers 152 and 153 moredifficult (e.g., which is preferred to render the underlayer morepermanent and robust).

Component 151 may include any suitable type of component, as process 100is especially useful with any component having edge features or othersharp transitions. Further, an underlayer such as layer 152 or 153 mayapplied to regions without a sharp transition to modify a spatialdimension of a coated component, assist in transitioning a coatingthickness across features of component 151, or a combination thereof. Inan illustrative example, process 100 may be applied to a metal orotherwise electrically conductive component for which a sufficientpowder coating layer thickness is required at one or more sharptransitions. For example, process 100 may be applied to electricallyconductive components having edges (e.g., machined or stamped) that areused near high voltage (e.g., a DC bus or power electronics system).

The use of an underlayer may minimize other otherwise reduce the amountof powder coating material needed to achieve a desired electricalinsulative property. Further, the use of an underlayer may eliminate orotherwise reduce machining and processing steps to soften sharptransitions. Further, the use of an underlayer may eliminate orotherwise reduce the need for more expensive insulative tape layers overthe powder coating layer. Further, application of an underlayer allows amore uniform resulting coated component in terms of thickness. Forexample, a uniform surface is more amenable to gluing or adhering ofadditional components during assembly.

FIG. 2 shows a flowchart of illustrative process 200 for using anunderlayer and mask to improve powder coating, in accordance with someembodiments of the present disclosure. Panel 250 illustrates process 200based on illustrative component 251. In an illustrative example, process200 includes applying a masking tape to any sharp transitions andrecesses of an object, powder coating the object, and leaving some ofthe masking tape on the object and removing some of the masking tape toexpose the object (e.g., while the object is used as intended).

Step 202 includes receiving a component (e.g., component 251) having atleast one edge feature (e.g., corners of component 251). The componentmay include a cooling component (e.g., a cooling plate or coolingjacket), a busbar (e.g., a terminal busbar of a battery pack), asidewall or battery module mounting bracket of a battery pack, any othersuitable component having an edge feature, or any combination thereof.Step 202 may include arranging the component (e.g., in a holder,fixture, or stand), selecting the component (e.g., based on part number,serial number, or type), preparing the component (e.g., grinding,sanding, etching, cleaning, or applying any other suitable preparation),any other suitable action, or any combination thereof.

Step 204 includes applying an underlayer to the at least one edgefeature. The underlayer (e.g., shown by layers 252 and 253) may includea tape such as, for example, a masking tape, a thermoset tape (e.g.,having a thermosetting epoxy embedded), a heat-activated tape, any othersuitable tape, or any combination thereof. The underlayer may beelectrically conductive, dielectric, thermally conductive, thermallyinsulative, or any suitable combination thereof. The underlayer may haveany suitable thickness profile. For example, an underlayer may have auniform thickness, a varying or tapered thickness, or a combinationthereof. In some embodiments, step 204 includes selecting the underlayerbased on the component received at step 202. As illustrated, anunderlayer may be applied to a recess feature of component. For example,as illustrated, layer 252 is applied to cover through recess 259 (e.g.,a through hole) on one face, in addition to edge features of component251. In some embodiments, an underlay is applied to a recess feature toensure a more uniform coating is applied to ensure a smoother radius ofcurvature at the location of the recess feature.

Step 206 includes applying a mask layer (e.g., layer 255 as illustrated)to the component. Layer 255 is configured to be removed after powdercoating, to expose a surface of component 251 that is not powder coated.To illustrate, the mask layer may be the same material as theunderlayer, or may be a different material. For example, in someembodiments, the mask layer and the underlayer include the samematerial, with one difference being that the mask layer is to be removedafter coating. In a further example, in some embodiments, the mask layerand the underlayer include a different material (e.g., the mask layerbeing relatively easier to remove after coating 254 is formed).

Step 208 includes applying a powder coat (e.g., shown by coating 254) tothe component and underlayer. Applying the powder coat may includepreparing the exposed surface, spraying a powder on the component andunderlayer, and curing the powder to form an overlayer. Preparing theexposed surface may include blasting with air to remove particles,blasting with particles to abrade the exposed surface, washing or othercleaning, plasma treating, performing any other suitable action toprepare for spraying, or any combination thereof. As illustrated, thepowder coat is applied on one side of component 251 (e.g., the otherside may be used for mounting or otherwise interfacing). In someembodiments, through recess 259, or any other suitable recess, may beleft open on or along at least one side to prevent a gas pocket fromforming during the powder coating process.

Step 210 includes removing the mask layer from the component. In someembodiments, for example, after coating 254 is applied, layer 255 isremoved to expose component 251. Layers 252 and 253 remain in place whenlayer 255 is removed. For example, process 200 may be used to ensure amore uniform coating 254 at the edges of component 251, while allowingregion 256 of component 251 to remain uncoated for further processing(e.g., for interfacing to another component). As another example,process 200 may be used to apply a uniform coating over through recess259. Without using layer 252 over through recess 259, the inner sides ofthe recess would have a thinner coating layer or no coating at all andfail design requirements. Any suitable combination of underlayers andmasking layers may be used in accordance with the present disclosure.

FIG. 3 shows stages of layering and coating illustrative coolingassembly 300, in accordance with some embodiments of the presentdisclosure. As illustrated, cooling assembly 300 includes three plates301, 302, and 303, which are assembled to form cooling channels (e.g.,one of which is cooling channel 309, as illustrated in FIG. 3 ). Forexample, plates 301, 302, and 303 may be brazed to form cooling assembly300. As illustrated, cooling assembly 300 includes a region having sharptransitions where the ends of plates 301, 302, and 303 come together(e.g., on the right side, as illustrated).

Layer 305 is applied to cooling assembly 300 to cover edge features ofcooling assembly 300, thus forming underlaid assembly 310. In someembodiments, for example, the size, thickness, and type of material usedto form layer 305 is determined based on component 300 (e.g., a radiusof curvature, material), a desired resulting assembly (e.g., resultingradius of curvature), an expected electrical environment, a desiredprofile for coating, any other suitable criterion, or any combinationthereof.

Coating 306 is applied to underlaid assembly 310 to form powder coatedassembly 320. If layer 305 were not in place, coating 306 would not beexpected to be as uniform at the sharp transitions of component 300.Further, layer 305 may provide electrical insulation as well, in somecircumstances (e.g., when powder coated assembly 320 is to be arrangednear metal components, a DC bus, or other potential circuits). In someembodiments, layer 305 may extend further along plates 301 and 303 toreduce the potential for peeling and corresponding failure modes.

FIG. 4 shows a perspective view of illustrative busbar 400, which hasbeen powder coated, in accordance with some embodiments of the presentdisclosure. Busbar 400 is configured to be included in a battery system(e.g., of an electric vehicle), and thus requires some electricalinsulation. As illustrated, busbar 400 includes powder coated region401, and exposed tabs 402. Exposed tabs 402 are configured to beelectrically coupled to one or more current collectors, and thus are notpowder coated. For example, exposed tabs 402 may be formed by process200 of FIG. 2 (e.g., particularly steps 206 and 210 thereof). Recesses403, 404, and 405 are covered by an underlayer and a subsequent powdercoating. Further, busbar 400 may include an underlayer at any suitableedge feature, recess, flat area, or a combination thereof to allow amore uniform powder coating thickness, improved electrical isolation, orboth. In an illustrative example, recesses 403, 404, and 405 may allowmounting of additional components, clearance for other components,weight reduction, mounting locations (e.g., during manufacturing), or acombination thereof.

FIG. 5 shows an illustrative mounting bracket 500, which has been powdercoated, in accordance with some embodiments of the present disclosure.Mounting bracket 500 (e.g., which may include a shear wall or otherstructural support) is configured to be included in a battery system(e.g., of an electric vehicle), to provide structural support, and thusrequires some electrical insulation. As illustrated, mounting bracket500 includes powder coated region 501, which covers an underlayer 503.Underlayer 503 covers recesses 502, such that after powder coating noexposed or thinly covered areas are present. For example, coatedmounting bracket 500 may be formed by process 100 of FIG. 1 , whereinthe underlayer is applied to sharp transitions of recess features.Further, mounting bracket 500 may include an underlayer at any suitableedge feature, recess, flat area, or a combination thereof to allow amore uniform powder coating thickness, improved electrical isolation, orboth.

Using an underlayer over recess features may provide additionalbenefits. In some embodiments, recesses 502 may have been added tomounting bracket 500 for weight saving purposes. In addition to creatingsharp edges, the recesses may cause other problems in the manufacturingprocess. For example, in some embodiments, mounting bracket 500 issecured to a battery module using an adhesive. However, the addedrecesses create paths through which the adhesive can spread duringassembly and curing. Accordingly, by using underlayer 503 over recesses502, this provides an additional benefit of blocking paths through whichthe adhesive can spread.

The foregoing is merely illustrative of the principles of thisdisclosure, and various modifications may be made by those skilled inthe art without departing from the scope of this disclosure. Theabove-described embodiments are presented for purposes of illustrationand not of limitation. The present disclosure also can take many formsother than those explicitly described herein. Accordingly, it isemphasized that this disclosure is not limited to the explicitlydisclosed methods, systems, and apparatuses, but is intended to includevariations to and modifications thereof, which are within the spirit ofthe following claims.

What is claimed is:
 1. An apparatus comprising: a cooling assembly of abattery system comprising: plates forming cooling channels and at leastone edge feature having a radius of curvature; an underlayer arrangedover the at least one edge feature, wherein the underlayer is configuredto increase the radius of curvature of the at least one edge feature;and a powder coating arranged over the cooling assembly and over theunderlayer to form a continuous layer, wherein the underlayer isconfigured to remain under the powder coating when operating in thebattery system.
 2. The apparatus of claim 1, wherein the plates areformed from sheet metal, wherein the at least one edge feature comprisesa joint at an edge of the sheet metal.
 3. The apparatus of claim 1,wherein the cooling assembly further comprises a region that is exposed,wherein the region does not coincide with the underlayer.
 4. Theapparatus of claim 1, wherein the underlayer is electrically insulative.5. The apparatus of claim 1, wherein the cooling assembly furthercomprises on or more recess features, and wherein the underlayer isarranged to cover the one or more recess features.
 6. The apparatus ofclaim 1, wherein the underlayer comprises a tape.
 7. The apparatus ofclaim 6, wherein the tape comprises at least one of a thermoset tape, amasking tape, or a heat activated tape.
 8. The apparatus of claim 1,wherein the underlayer comprises a thickness, and wherein thickness isselected to provide a predetermined spatial dimension of the apparatus.9. The apparatus of claim 1, wherein the plates comprises anelectrically conductive material.
 10. An apparatus comprising: a coolingassembly comprising at least one edge feature having a radius ofcurvature, wherein the cooling assembly is electrically conductive; anunderlayer arranged over the at least one edge feature, wherein theunderlayer is configured to increase the radius of curvature of the atleast one edge feature; a second component arranged a distance from thecooling assembly, wherein the second component is electricallyconductive; and a powder coating arranged over the cooling assembly andover the underlayer to form a continuous layer, wherein the underlayeris configured to remain under the powder coating, and wherein theunderlayer provides dielectric protection against shorting between thecooling assembly and the second component when operating.
 11. A methodfor coating a cooling assembly of a battery system, the cooling assemblycomprising plates forming cooling channels and at least one edgefeature, the method comprising: applying an underlayer to a first regionof the cooling assembly to form an underlaid cooling assembly, whereinthe first region comprises the at least one edge feature, wherein the atleast one edge feature comprises a first radius of curvature, andwherein the underlayer comprises a second radius of curvature at the atleast one edge feature larger than the first radius of curvature; andapplying a powder coating to the underlaid cooling assembly to form acoated cooling assembly having a continuous powder coating layer,wherein the underlayer is configured to remain on the coated coolingassembly under the powder coating when operating in the battery system.12. The method of claim 11, wherein the underlaid cooling assemblycomprises an exterior surface, the method further comprising preparingthe exterior surface for the powder coating.
 13. The method of claim 11,further comprising applying a masking layer to a second region of thecooling assembly, wherein the first region and the second region do notoverlap.
 14. The method of claim 13, further comprising removing themasking layer after applying the powder coating to expose the secondregion of the cooling assembly.
 15. The method of claim 11, whereinapplying the powder coating comprises: spraying a powder onto theunderlaid cooling assembly; and curing the powder to from the continuouspowder coating layer, wherein curing the powder coating comprisesincreasing a temperature of the underlaid cooling assembly.
 16. Themethod of claim 11, wherein applying the underlayer comprises applying atape to the first region, wherein the tape comprises at least one of athermoset tape, a masking tape, or a heat activated tape.